import functools


def log(descriptor="default"):
    def decorator(func):
        @functools.wraps(func)
        def wrapper(*args, **kw):
            print("begin")
            print("%s %s" % (func.__name__, descriptor))
            return func(*args, **kw)
        return wrapper
    print('end')
    return decorator


@log()
def now(s):
    print(s)

now('Hello')
